This invention relates to delivery systems for implanting endoluminal devices within the human or animal body for treatment of endovascular disease. In particular, this invention relates to delivery systems having a novel catheter system to cannulate a contralateral portion of an endoluminal device.
The functional vessels of human and animal bodies, such as blood vessels and ducts, occasionally weaken or even rupture. For example, the aortic wall can weaken, resulting in an aneurysm. One surgical intervention for weakened, aneurismal, or ruptured vessels involves the use of stent grafts to replace or repair the vessel. Stent grafts may be formed from a tube of a biocompatible material in combination with one or more stents to maintain a lumen therethrough. The stents are attached to the graft material in a number of ways, including by suturing the stent to the graft material, embedding the stent in the graft material, adhesively attaching the stent to the material and the like.
The above-described examples are only some of the applications in which endoluminal devices are used by physicians. Many other applications for endoluminal devices are known and/or will be developed in the future. For example, in addition to the use of stents and stent-grafts to treat vascular stenoses and aneurysms, similar procedures also may be used to deploy vascular filters, occluders, artificial valves and other endoprosthetic device.
A prosthesis of this type can, for example, treat aneurysms of the abdominal aortic, iliac, or branch vessels such as the renal arteries. Hence, an endoluminal prosthesis can be of a unitary construction or be comprised of multiple prosthetic modules. A modular prosthesis allows a surgeon to accommodate a wide variation in vessel morphology while reducing the necessary inventory of differently sized prostheses. For example, aortas vary in length, diameter and angulation between the renal artery region and the region of the aortic bifurcation. Prosthetic modules that fit each of these variables can be assembled to form a prosthesis, obviating the need for a custom prosthesis or large inventories of prostheses that accommodate all possible combinations of these variables. A modular system also may accommodate deployment by allowing the proper placement of one module before the deployment of an adjoining module.
Modular systems are typically assembled in situ by overlapping the tubular ends of the prosthetic modules so that the end of one module sits partially inside the other module, preferably forming circumferential apposition through the overlap region. This attachment process is sometimes referred to as “tromboning.” The connections between prosthetic modules are typically maintained by the friction forces at the overlap region and enhanced by the radial force exerted by the internal prosthetic module on the external prosthetic modules where the two overlap. The fit may be further enhanced by stents fixed to the modules at the overlap region or other treatment of the graft material at the connection points.
For example, in the treatment of an abdominal aortic aneurysm, a bifurcated device including a main body and two limbs may be deployed within the aneurysm. Further extension of one or more of the limbs into their corresponding iliac arteries may be desired for full repair of the aneurysm. With some bifurcated devices, one of the limbs may extend into a corresponding iliac artery, while the other limb, for example a shorter limb (referred to here as the contralateral limb) does not.
In this case, the shorter limb may remain in the body of the aneurysm above the opening of its respective iliac artery. In order to extend this limb into its respective iliac artery one or more extensions may be used in an overlapping manner, as described above, to extend the shorter limb into the iliac artery.
Normally, extension of the contralateral limb is accomplished by inserting a guide wire through the femoral artery associated with the iliac artery in which leg extensions are to be inserted and overlapped with the contralateral limb of the body. The wire is inserted into the femoral artery, up through the iliac artery, into the aneurysmal space and then, desirably, is manipulated to be inserted into the contralateral limb of the main prosthesis.
A prosthetic module then is advanced up the guide wire, and partially inserted into the contralateral limb of the bifurcated prosthesis in an overlapping manner. The module is then expanded to contact the limb and seal against the limb. This procedure can be performed to attach several sequential modules as needed to extend the contralateral limb. Similar extension may be performed on the other limb if needed.
This insertion process, though effective, difficulties may arise in the cannulation of the shorter limb, particularly in cases where the vascularity is tortuous, a common issue; where the graft is short bodied, thus increasing the distance between the femoral artery access site and the prosthesis target site; or when the shorter limb is located within the aneurysm, thus presenting a large space in which the guidewire must navigate to reach the shorter limb. In addition, blood continues to flow through the vessel, which may further contribute to movement of the wire during placement.
Thus, this procedure requires both high precision and accuracy on the part of the physician performing the procedure as the aneurysmal sac may be large. Timing also is an important factor. Proper wire placement in this situation may take multiple attempts and, in some cases, be impossible. Hence, placement of the wire may be time consuming and unpredictable. With patients suffering from aneurysms, time is a critical factor, as an aneurysm may rupture at any time.